The small number of E6 labs left only tells you something about the demand for E6 film at CURRENT PRICES.
Current prices for E6 film are prohibitively high for many people who would otherwise buy it in addition to C41. This is an unnatural state for the market to be in, as Fuji currently has a monopoly on E6. As was bound to happen, this will be remedied by the introduction of Ektachrome, and, due to the resulting competition, prices will fall. More E6 will be bought, shot, and developed, stabilizing the decline in E6 labs and possibly even inducing more of them to enter the market.
The reason we know that sufficient demand will be there at the future lower price is by watching the behavior of the price of the film when the supply is severely restricted due to discontinuation, as I mentioned in my earlier post.
Somebody might want to draw the supply and demand curves for this to make it more clear, as I am currently going to bed.
Is there an actual economist in the house who can either confirm or refute my theory? I am actually curious.